1. Field of the Invention
The invention relates to the field of production printing systems and, in particular, to an ink tray that has an open bottom section so that printhead arrays in the production printing system may be inspected or cleaned through the bottom of the ink tray.
2. Statement of the Problem
Businesses or other entities having a need for volume printing typically purchase a production printing system. A production printing system comprises a high-speed printer used for volume printing, such as 100 pages per minute or more. The production printing systems are typically continuous-forms printers that print on paper or some other printable medium that is stored on large rolls. Some continuous-forms printers are able to print on paper up to 20 inches wide or more.
A production printing system typically includes a localized print controller that controls the overall operation of the printing system, and one or more print engines (sometimes also referred to as an “imaging engine” or as a “marking engine”). The print engines include a printhead controller and arrays of printheads. An individual printhead includes multiple tiny nozzles (e.g., 360 nozzles per printhead depending on resolution) that are operable to discharge ink as controlled by the printhead controller. The printhead array is formed from multiple printheads that are spaced in series along a particular width, such as 20 inches.
When in operation, the printable medium is passed underneath the printhead arrays while the nozzles of the printheads discharge ink at particular intervals to form pixels on the medium. There are times when the printheads discharge ink outside of the margin of the printable medium. For example, the printing system may run a cleaning cycle which causes each nozzle to discharge ink even when the printable medium is not positioned underneath the printheads. The cleaning cycle is run periodically to avoid clogging of the nozzles. In another example, the printing system may be printing on a medium that is less than the width of the printhead array. For example, a printing system having 20 inch arrays may be printing on an 8.5 inch medium. Instead of shutting off the printheads or nozzles that are not being used to print to the medium and risking that the unused nozzles become clogged, the printheads outside of the margin of the medium are still turned on periodically to avoid clogging. When the printheads discharge ink and there is no printable medium underneath the printheads, the ink being discharged would make an undesirable mess if the ink were not captured in some manner.
Presently, ink trays are affixed or fastened to the printing system opposite the printheads and facing the printheads when they are in a printing position (as opposed to a parked position). The ink trays have a width at least as wide as the printhead arrays, and typically a sponge or some other ink absorbing element is placed within the ink trays. Thus, when the printheads discharge ink outside of the margin of the medium, the ink is absorbed by the ink absorbing elements in the ink trays. The ink trays are open at the top and enclosed at the bottom to act as a container. When the ink absorbing elements within the ink trays become saturated, the excess ink is contained in the ink trays.
One problem with present printing systems is that the printheads are not visible to the printer operator when the printhead arrays are in the printing position. As described above, when the printhead arrays are moved to the printing position, the printhead arrays are directly facing the ink trays (i.e., within a few millimeters) so that the ink trays may absorb or capture any excess ink that is discharged outside of the margins of the medium. If the printer operator wants to inspect or clean the printheads while the printhead arrays are in the printing position, he/she would not be able to as the ink trays would be blocking the printhead arrays. Thus, the printer operator would have to detach the ink trays from the printing system in order to inspect the printhead arrays. Unfortunately, the ink trays are affixed or fastened to the printing system in a rigid but removable fashion. For example, ink trays in some printing systems are bolted to frame of the printing system on either one end or both ends. Thus, to remove the ink trays, the printer operator has to remove the bolts, screws, or another fastening member from the ink trays, and then attempt to remove the ink trays from the printing system. Removal of the ink trays may then require sliding, twisting, or otherwise manipulating the position of the ink trays in order to detach it from the frame, and extricate it from the printing system. Removing the ink trays can be time consuming, and the printer operator may accidently spill ink that is being contained in the ink trays while attempting to remove the ink trays.